Environment Report 2017

ENVIRONMENT REPORT 2017

5.2 Accidental Oil Releases in Context In 2016, there were 287 unplanned oil releases, from which almost 115 tonnes of oil were released to the marine environment. To put this into context, in the same year, approximately 2,000 tonnes of oil were discharged to sea in produced water, under permit, on the UKCS. This means that accidental oil releases represented 5.7 per cent of the total oil that entered the marine environment. Furthermore, 85.1 million tonnes of oil equivalent were produced in 2016, meaning that accidental oil releases represented less than 0.00014 per cent of total oil production. There were 23 more releases in 2016 than there were in 2015, and a five-fold increase (from 24 tonnes to 115 tonnes) in the amount of oil accidentally released. This is due to a single large release (approximately 95 tonnes of crude oil). Excluding this one outlier, the total for the 286 remaining releases was nearly 20 tonnes. The average size of reported accidental oil releases has varied each year from between 0.10 tonnes and 2.11 tonnes since 2010, and is affected by the low frequency, high mass releases mentioned above. In 2016, the average mass of oil released per occurrence was 0.4 tonnes, lower than the average of 0.6 tonnes for 2010-16. When the exceptional single release is excluded, this falls to around 0.07 tonnes per release in 2016 16 . International Comparison International comparisons are not straightforward, as differences in the legislative and cultural norms in the industry worldwide can lead to different reporting behaviours. However, the IOGP 17 reported a worldwide total of 4,564 accidental releases in 2016, 842 of which were greater than one barrel of oil equivalent (boe). Eleven per cent of the releases (547 tonnes) were from offshore installations, resulting in 0.1 tonnes being accidentally released per million tonne of offshore production globally. The same dataset gives a European average of 0.5 tonnes released per million tonne of offshore hydrocarbon production. In comparison, the UKCS reported approximately 0.29 tonnes accidentally released per million tonne of hydrocarbon production in 2015, and 1.35 tonnes in 2016, a figure that was significantly increased by the single high mass release that was reported in 2016. Excluding that outlier, around 0.23 tonnes were released per million tonne of production. To put this further into context, after a two-year period in which the UKCS performed better than the Norwegian sector of the North Sea, Norway saw 0.17 tonnes accidentally released per million tonnes of hydrocarbons produced in 2015, falling to 0.07 tonnes in 2016. The average mass released per reported spill was 0.37 tonnes in Norway 18 .

16 It should be noted that 11 releases remain under review and so do not have final masses assigned to them. 17 See IOGP Environmental Performance Indicators 2016 at http://www.iogp.org/data-series 18 The Norsk Olje & Gass Environmental Report 2017 is available to download at www.norskoljeoggass.no/en/Publica/Environmental-reports

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